ElectroCat (Electrocatalysis Consortium)Overview Timeline • Start date (launch): Feb 1, 2016 ......

2017 Hydrogen and Fuel Cells Program Annual Merit Review – Slide 1This presentation does not contain any proprietary, confidential, or otherwise restricted information

Project ID: FC160

ElectroCat (Electrocatalysis Consortium)Piotr Zelenay

Los Alamos National LaboratoryLos Alamos, New Mexico 87545

Deborah MyersArgonne National Laboratory

Lemont, Illinois 60439

Hydrogen and Fuel Cells Program2017 Annual Merit Review and Peer Evaluation Meeting

Washington, DC – June 5-9, 2017

2017 Hydrogen and Fuel Cells Program Annual Merit Review – Slide 2

Overview

Timeline

• Start date (launch): Feb 1, 2016• End date: Sep 30, 2020

Budget

• FY16 funding: $2,100K• FY17 funding: $3,500K• Total FY16 - FY17: $5,600K

Barriers

• A. Cost (catalyst)• D. Activity (catalyst; MEA)• B. Durability (catalyst; MEA)• C. Power density (MEA)

Note: This is the first evaluation of ElectroCat at a DOE Annual Merit Review.

Partner – PI

Los Alamos National Laboratory

– Piotr Zelenay

Argonne National Laboratory

– Deborah Myers

National Renewable Energy Laboratory

– Huyen Dinh

Oak Ridge National Laboratory

– Karren More


PGM Stack Cost Breakdown (500,000 systems/year)

Relevance: Fuel Cell Stack Cost Challenge

0

0.2

0.4

0.6

0.8

1Peak Energy Efficiency

Power Density650 W/L

Specific Power650 W/kg

Cost$40/kW

Ultimate target:$30/kW

Start from -20 °C30 s

Durability5,000 h

Fuel cell system targets set to be competitive with ICEVs

Durability and cost are the primary challenges to fuel cell

commercialization and must be met concurrently

ElectroCat created as part of in February 2016

Goal: Accelerate the deployment of fuel cell systems by eliminating the use of PGM catalysts

PGM-based System Automotive Stack Status

https://www.hydrogen.energy.gov/pdfs/16020_fuel_cell_system_cost_2016.pdf


Approach: ElectroCat Objectives and Lab RolesMission: Develop and implement PGM-free catalysts and electrodes by streamlining accessto unique synthesis and characterization tools across national labs, developing missingstrategic capabilities, curating a public database of information.

LANL: PGM-free catalyst development, electrochemical and fuel cell testing, atomic-scale modelingANL: High-throughput techniques, mesoscale models, X-ray studies, aqueous stability studiesNREL: Catalyst modification, model catalyst development, advanced fuel cell characterizationORNL: Advanced electron microscopy, atomic-level characterization, XPS studies


Approach: Performance Targets

Fuel Cell Technologies Office Multi-Year Research, Development, and Demonstration Plan - Section 4.4 Fuel Cells, DOE 2016

PGM-free activity target equivalent to PGM activity target:0.44 A/mgPGM × 0.1 mgPGM/cm2

(electrode area) → 0.044 A/cm2

Table 3.4.7 Technical Targets: Electrocatalysts for Transportation Applications

Characteristic Units 2015 Status 2020 Targets

Platinum group metal total content (both electrodes)

g / kW (rated, gross) @ 150 kPa (abs)

0.16 0.125

Platinum group metal (pgm) total loading (both electrodes)

mg PGM / cm2 electrode area 0.13 0.125

Mass activity A / mg PGM @ 900 mViR-free >0.5 0.44

Loss in initial catalytic activity % mass activity loss 66 <40

Loss in performance at 0.8 A/cm2 mV 13 <30

Electro catalyst support stability % mass activity loss 41 <40

Loss in performance at 1.5 A/cm2 mV 65 <30

PGM-free catalyst activity A / cm2 @ 900 mVIR-free 0.016 >0.044


Approach: FY16 MiIestone, FY17 LANL and ANL QPMs

Date LANL Quarterly Progress Measures StatusDecember 2016(FY17 Q1)

Develop draft TT/A plan for ElectroCat and receive feedback from member national laboratories.

Completed(see Slide 11)

March 2017(FY17 Q2)

Synthesize and, in collaboration with other ElectroCat partner laboratories, characterize and evaluate ORR activity of PGM-free catalysts based on di-iron complexes.

Completed(see Slide 41,

Back-up)

June 2017(FY17 Q3)

Synthesize and demonstrate atomic dispersion of Fe sites in (Zn, Fe)-PSIE-MOF-derived catalyst; provide samples to ANL for further development of high-throughput screening techniques.

On track

Date ElectroCat Annual Milestone StatusSeptember 2016(FY16 Q4)

Establish a web-based Portal for the Consortium through which industry and university partners can easily and quickly identify the Consortium tools that would be most useful to them.


Date ANL Quarterly Progress Measures StatusDecember 2016(FY17 Q1)

Achieve half-wave potential agreement of <20 mV between RDE and m-CFDE ORR measurements for a benchmark PGM-free catalyst.

Completed (with E½agreement of < 30 mV)

March 2017(FY17 Q2)

Select and prepare six PGM-free electrode specimens and obtain 3-D micro-structures using synchrotron XCT.

Completed(for 7 ADC electrodes)

June 2017(FY17 Q3)

Demonstrate current densities in the combinatorial MEA for all twenty-five electrodes within 10% of those in a standard 5 cm² test cell using identical PGM-free electrode compositions in both cells.

On track

FY16

FY17


Approach: FY17 NREL QPMs

Date NREL Quarterly Progress Measures StatusDecember 2016(FY17 Q1)

Demonstrate F-doping onto LANL’s PGM-free catalyst (e.g., Fe-CM-PANI-C catalyst) with either CF4 or F2.


March 2017(FY17 Q2)

Demonstrate the synthesis of the M-C-N model catalyst with the chemical composition comparable to state of the art literature, and study its structural properties. The first target moiety is a nitrogen coordinated transition metal center in a carbon matrix, e.g., FeN4 in graphene matrix.


June 2017(FY17 Q3)

Demonstrate improved feasibility of segmented cell system for combinatorial PGM-free samples (e.g., Fe-CM-PANI-C catalyst) to minimize cross-talk of a one electrode layer with gradient composition and allow for a sufficient resolution and data interpretation. Based on availability, demonstration performed either with standard (i.e., non-combinatorial) PGM-free samples or first generation combinatorial Pt or PGM-free samples

On track

September 2017(FY17 Q4)

Extract values for the reaction order with respect to oxygen partial pressure and activation energy as a function of PGM-free catalyst type and/or electrode design. Utilize these extracted values to help determine the reaction mechanism for said PGM-free electrocatalyst (e.g., Fe-CM-PANI-C catalyst).

On track

FY17


Approach: FY17 ORNL QPMs, MiIestone and Go/No-Go Decision

Date ElectroCat Go/No-Go Decision Criteria DecisionJune 2017(FY17 Q3)

TT/A Process: Continuation of current path toward establishing a technology transfer and agreement (TT/A) process.

Short-form agreement for rapidly engaging industry established.

TBD

Date ElectroCat Annual Milestone StatusSeptember 2017(FY17 Q4)

Demonstrate 20 mA cm-2 at 0.90 V (iR-corrected) in an H2-O2 fuel cell and 100 mA cm-2 at 0.80 V in an H2-air fuel cell (measured); maintain partial pressure of O2 + N2 at 1.0 bar (cell temperature 80 °C).

On track(see Slide 13)

Date ORNL Quarterly Progress Measures StatusDecember 2016(FY17 Q1)

Characterize at least three new candidate PGM-free catalysts using STEM imaging and analysis and XPS. Completed

March 2017(FY17 Q2)

Coordinate characterization effort at ORNL with high-throughput combinatorial results from ANL towards down-selecting potential catalysts for in-depth structural and chemical analyses.

On track

June 2017(FY17 Q3)

Coordinate 3D electron tomography effort at ORNL with 3D X-ray tomography efforts from both ANL and LANL. On track

FY17


http://www.electrocat.org/capabilities/

Synthesis, Processing and ManufacturingSynthesis and post-synthesis processing of PGM-free catalysts in high-surface-area form or as planar model systems, and fabrication of electrode layers and MEAs High surface area catalysts Model systems synthesis Fabrication of electrodes and membrane-electrode assemblies

Characterization and TestingComposition, structure, and performance of high-surface-area PGM-free catalyst powders, catalyst-ionomer inks, electrode layers, membrane electrode assemblies, and thin film model catalysts. Materials Characterization Electrode/Cell Characterization & Diagnostics Model Systems Characterization

Computation, Modeling and Data Management Guiding and complementing experimental efforts with computational and modeling capabilities at the catalyst, electrode, and membrane electrode assembly levels, as well as by data management expertise. Modeling structure-function relationships Methods and models to characterize behavior Systems for handling and correlating data

Accomplishment: Capabilities Posted on ElectroCat Website

Milestone: FY16 ElectroCat milestone completed (FY16 Q4)


Accomplishment: Data Hub Established

Data Hub Team Activities:

• Established monthly Data Team meetings with PIs to discuss ongoing data efforts

• Leveraging Globus data publication and Globus search services for prototype Data Hub

Data Hub features to be implemented:

• Capability to mint DOIs or other permanent identifiers with persistent landing pages for datasets

• Support for publishing datasets with sizes ranging from kB to TB

• Tools to support automated data capture and publication

• Capabilities to share datasets internally and externally

Web user interface (UI) for general access

Python and REST interfaces to support automation and scripting

Prototype Data Hub for Internal Group (available)


Accomplishment: Technology Transfer and Agreements (TT/A)

• Industry Engagement Plan (IEP) – finalized and agreed upon

• Multi-Laboratory Non-Disclosure Agreement(NDA) – executed

• Intellectual Property Management Plan (IPMP)– in process

• Material Transfer Agreement (MTA) – in process• CRADA Template – complete; previously agreed

upon format; available for use• Tech Transfer and Agreements group conference

call held in March 2017 to discuss TT/A strategy and status update

Highlight: FY17 Q1 Quarterly Progress Measure Completed


SampleBET surface

area(m2 g-1)

Micropore surface area

(m2 g-1)

(CM+PANI)-Fe-C-1000 716 880

(CM+PANI)-Fe-C(Zn)-1000 1029 1086

Progress: (CM+PANI)-Fe-C(Zn) Catalyst

ZIF-8

Zn salt used instead of Zn-MOF to synthesize highly porous catalyst at temperatures above 900 °C

Relative pressure (P/P0)0.0 0.2 0.4 0.6 0.8 1.0

Volu

me

adso

rbed

(cm

3 g-1

STP

)

0

200

400

600

800

(CM+PANI)-Fe-C-1000(CM+PANI)-Fe-C(Zn)-1000

Half pore width (nm)0.0 0.5 1.0 1.5 2.0

dS(r

) (m

²/Å/g

)

0

400

0

400


Current density (A cm-2)

0.0 0.2 0.4 0.6 0.8 1.0 1.2

Volta

ge (V

)

0.0

0.2

0.4

0.6

0.8

1.0

HFR

(Ω cm

2)

0.0

0.2

0.4

0.6

0.8

1.02016 Performance (AMR)2017 Performance via magnetic purification2017 Improved performance via combination ofmagnetic purification and not hot pressing MEA

Accomplishment: Fuel Cell Performance of (CM+PANI)-Fe-C(Zn) Catalyst

Anode: 0.3 mgPt cm-2 Pt/C H2, 200 sccm, 1.0 bar H2 partial pressure; Cathode: ca. 4.8 mg cm-2 air, 200 sccm, 1.0 bar air partial pressure;

Membrane: Nafion,211; Cell: 5 cm2, 80 °C

• Kinetic region improved by increasing micropore surface area by Zn evaporationand removing spectator magnetic Fe species (magnetic purification, see Slide 41)

• Mass transport region is further improved by removing hot pressing step


0.0 0.2 0.4 0.6 0.8 1.0 1.2

iR-fr

ee v

olta

ge (V

)

0.2

0.4

0.6

0.8

1.0

25 wt%35 wt%45 wt%55 wt%

Nafion content

Effect of Nafion® Content

Ionomer content(wt. %) 25 35 45 55

iR-free currentdensity at 0.8 V

(mA cm−2)65 90 110 120

Highlight: Improved fuel cell performance in both kinetic and mass transport region reaching a current density of 120 mA/cm2 at 0.8 V (iR-free)


Progress: Effect of Ionomer Content and Equivalent Weight (EW)Anode: 0.3 mgPt cm-2 Pt/C H2, 200 sccm, 1.0 bar H2 partial pressure; Cathode: (CM+PANI)-Fe-C(Zn) ca. 4.8 mg cm-2 (not hot-pressed), air, 200 sccm, 1.0 bar

air partial pressure; Ionomers: Nafion D521 (EW 1100), Aquivion D83 (EW 830), Aquivion D72 (EW 720); Membrane: Nafion,211; Cell: 5 cm2, 80 °C

130

120

110

100

720 830 110025

35

45

55iR-free current density at 0.8 V (mA/cm2)

Iono

mer

Con

tent

(wt.

%)

EW (g/mol SO3H)

50

60

70

80

90

100

110

120

130

400

380

360340

720 830 110025

35

45

55Electrochemical surface area (m2/g)

Iono

mer

Con

tent

(wt.

%)

EW (g/mol SO3H)

180

220

260

300

340

380

420

Increasing ionomer content from 25 wt% to 55 wt% improves kinetic performance thanks to higher catalyst utilization, i.e., higher electrochemically-active surface area (ECSA)

150 200 250 300 350 400 45040

60

80

100

120

140 EW = 720 EW = 830 EW = 1100

iR-fr

ee j

at 0

.8 V

(mA

/cm

2 )

ECSA (m2/g)


Accomplishment: In situ RDE-ICP/MS of PGM-Free Catalysts

• Fe dissolution rate following redox transition at ca. 0.65 V, with higher rate measured on the negative side of the redox couple potential; no Zn dissolution detected during cycling up to 1.2 V

• No change in ORR activity of (AD)Fe-N-C after 100 potential cycles

LANL (AD)Fe-N-C: 0.3 mg/cm2; potential cycling range: 0.08 - 1.2 V vs. RHE; RDE at 100 rpm

ICP-MS

Fe

Zn

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

Fe D

isso

lutio

n R

ate

(ng

cm-2

s-1 )

AD(Fe)-N-C (CM+PANI)-Fe-C (Zn)

~ 0.2 at% Fe in both (AD)Fe-N-C and (CM+PANI)-Fe-C(Zn)

Highlight: Fe dissolution rates for (AD)Fe-N-C are >10× lower than for (CM+PANI)-Fe-C(Zn)

MOF-derived atomically dispersed (AD)Fe-N-C PGM-free catalyst


Progress: Increased Iron Utilization in PGM-free Catalysts

(AD)Fe-N-C PGM-free catalyst: Homogenous carbon structure

SE Image TEM Image

Highlight: No crystalline Fe species observed already after the first heat treatment step → increased Fe utilization

Carbon plates, ~0.2 μm wide and 1.5-2.0 μm long, with enhanced microporosity due to Zn evaporation → much improved accessibility to ORR active sites


Accomplishment: (AD)Fe-N-C PGM-free ORR Catalyst

ORR: 0.6 mg cm-2; 0.5 M H2SO4; 900 rpm; 25ºC; Hg/HgSO4(0.5 M H2SO4) reference electrode; graphite counter electrode;

steady-state potential program: 20 mV steps, 20 s/step;

H2O

2 yie

ld (%

)

0

5

10

Potential (V vs. RHE)0.0 0.2 0.4 0.6 0.8 1.0

Cur

rent

den

sity

(mA

cm-2

)

-3.5

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

E1/2 = 0.83 V

Highlight: Atomically dispersed Fe catalyst showing very high ORR activity in RDE testing (E½ of 0.83 V) and excellent 4e- selectivity (H2O2 yield < 1.5 %)

Iron atomically dispersed (dark yellow) in N-doped carbon; no Fe particles observed


Accomplishment (Major): Direct Detection of Fe Sites on (AD)57Fe-N-C

• 57Fe-enriched catalyst demonstrating the same properties as non-enriched catalyst: atomically dispersed iron seen (solid yellow line), with some Fe-clustering (dashed yellow line)

• Nuclear resonance vibrational spectroscopy (NRVS) used with NO as a molecular probe (an O2analog) to detect iron sites on (AD)57Fe-N-C catalyst; vibrational feature for NO-treated catalyst at a frequency of 450 cm-1, likely corresponding to the Fe-NO bond stretch (assignment pending)

Energy (cm-1)

0 200 400 600 800

pDO

S (c

m)

Electrochemically reducedNO treated

Energy (cm-1)

400 450 500

pDO

S (c

m)

Highlight: Direct evidence of the presence of Fe sites on the surface of a PGM-free catalyst!


Progress: X-ray Absorption Study of (AD)Fe-N-C Active Site

0.0

0.5

1.0

1.5

2.0

7100 7120 7140 7160

Fluo

resc

ence

Inte

nsity

Energy (eV)

As-prep (AD)Fe-N-CReduced (AD)Fe-N-CRed. (AD)Fe-N-C in NOFeSO4Fe2O3

Reduced (AD)Fe-N-CReduced (AD)Fe-N-C with NO

• Fe coordination number in reduced catalyst consistent with predominant composition of four-coordinated Fe-(N,C,O) species

• During NO exposure, coordination number increased by ~1 and bond distance decreased by ~3%

• Coordination number increase of ~1 consistent with the majority of Fe sites coordinating NO (i.e., located on the surface of the catalyst)

1.80

1.85

1.90

1.95

2.00

2.05

2.10

2.15

2.20

1

2

3

4

5

6

7

Reduced catalyst Reduced catalystduring NO exposure

Fe-N,C

,O bond length (Å)Fe

coo

rdin

atio

n nu

mbe

r


Progress: In situ XAFS during Heat Treatment

• Six catalysts studied simultaneously• Precursor highly oxidized at room temperature• Fe species reduced at ~500°C• Fe species found in ORR active catalyst formed at ~620-700°C• Fe species not changing during cooling step or upon exposure

to air at room temperature

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

7100 7120 7140 7160

Nor

mal

ized

Abso

rptio

n

Energy (eV)

22

489

517

535

565

1000

After_Pyr_RT_He

After_Pyr_RT_Air

Room temp. before

~570°C

~500°C

~1000°C;Room

temp. after pyrolysis and air

exposure

Room temp (RT)

490°C

520°C

535°C

565°C

1000°C

After pyrolysis, RT He

After pyrolysis, RT air

5 at% (AD)Fe-N-C during heat treatment


Progress: (AD)Fe-N-C Catalyst Fuel Cell Performance


0.0 0.2 0.4 0.6

Volta

ge (V

)

0.0

0.2

0.4

0.6

0.8

1.0

HFR

( Ωcm

2 )

0.0

0.2

0.4

0.6

0.8

1.0iR-freeMeasuredHFR

75 – 90 μmAnode: 0.2 mgPt cm-2 Pt/C H2, 200 sccm, 1.0 bar H2 partialpressure; Cathode: 8.0 wt% Co catalyst air, 200 sccm, 1.0bar air partial pressure; Membrane: Nafion,211; Cell: 80°C

• Dense (AD)Fe-N-C catalyst layer with uniformdistribution of catalyst, but non-optimized ionomerdistribution (see ionomer aggregates in fluorine mapand nano-CT image)

• Low fuel cell performance caused by dense packingof catalyst layer resulting in uneven ionomerdistribution and low porosity

~𝟏𝟏𝟏𝟏 𝝁𝝁𝝁𝝁


00.5

11.5

22.5

33.5

4

0.00 0.25 0.50 0.75 1.00

j/j ce

ll

xCL

0.80 V0.55 V0.20 V

1 bar air

0

50

100

150

200

250

300

0 0.25 0.5 0.75 1

Resi

stan

ce, s

/m

Current Density, A.cm-2

CL PoresCL Average Film

85 μm thick electrode

0

10

20

30

40

50

60

0 0.25 0.5 0.75 1 1.25 1.5

Resi

stan

ce, s

/m


CL Pores

CL Average Film

10 μm thick electrode

𝛿𝛿𝑤𝑤 =𝛿𝛿𝑖𝑖𝜖𝜖𝑣𝑣𝑆𝑆𝜖𝜖𝑁𝑁

Purpose: Determine cathode properties limiting performance as a function of cell operating conditions and identify means for improving performance

Progress: PGM-free Cathode Catalyst Layer Model

Cathode model for quantification of mass transport losses• Bundle-of-capillaries model to determine electrode water

retention curves

Distributed ORR Kinetics• In pure O2, ORR mainly confined to the membrane boundary• In air, ORR zone broadens and shifts towards diffusion media

due to transport resistance in pores

Data shown for (CM+PANI)-Fe-C

O2 mass transport losses are dominated by flooded pores in thick electrodes and film resistance in thin electrodes


Electrode tortuosity

Progress: Methods for Improving High Current Density PerformanceHighlight: High current density performance improved by decreasing electrode thickness, tortuosity

(m), and size of micropores (rm) and increasing volume fraction (vf) of micropores

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Pote

ntia

l, V


110 um85 um60 um40 um20 um10 um

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Pote

ntia

l, V


m=1.00m=1.25m=1.50m=1.75m=2.00

𝐷𝐷_𝑒𝑒𝑓𝑓𝑓𝑓=𝐷𝐷_𝑏𝑏𝑢𝑢𝑙𝑙𝑘𝑘 ((1−𝑠𝑠) 𝜖𝜖_𝑣𝑣 )𝑚𝑚

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1 1.2 1.4

Pote

ntia

l, V


rm=18 nmrm=14 nmrm=10 nm

Electrode thickness Micropore size

Micropore size and volume fraction

0

0.2

0.4

0.6

0.8

1

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6

Pote

ntia

l, V


rm=18 nm,vf=0.28rm=14 nm,vf=0.39rm=10 nm,vf=0.53


Progress: Durability Descriptor Calculation Automation (DDCA)

(2) Structure Relaxed(3) DDCA Setup Script:

input of atoms and energy ranges to test

(6) DDCA Analysis Script:determine KODTE for

each atom (7) Durability Descriptor for Input Structure

(4) Ab-initio Molecular Dynamics(AIMD) Simulations

(100 fs)

ORR Activity Calculations

(1) Input Structure:

FeN4(*OH) - ZZ edge

70 kV e- impacting N of FeN4 complex at ZZ edge

Zobelli, et al., PRB 75, 245402 (2007)

(5) DDCA Visualization Script:generate movies of AIMD

calculations in automated fashion

Highlight: Successful automation of setup, calculation/submission, visualization, and

durability descriptor analysis


Accomplishment: Establishment of KODTE Library

Findings thus far: • N most susceptible to e- beam damage → lowest knock-on

displacement threshold energy (KODTE) in all considered cases• Edge atoms more susceptible than bulk even for carbon

supports, edge atom has lowest KODTE• No large dependence on metal (M) speciation calculated• No large dependence on *OH ligand calculated• Need to test N-coordination (MN3 structure) and other possible

structural effects

Structure KODTE (kV)FeN4 bulk 90FeN4OH bulk 90MnN4 bulk 90MnN4OH bulk 90CoN4 bulk 90CoN4OH bulk 90FeN4 arm chair 35*FeN4OH arm chair 30*MnN4 arm chair 35*MnN4OH arm chair 25*CoN4 arm chair 35*CoN4OH arm chair 30*FeN4 zig zag 70FeN4OH zig zag 70MnN4 zig zag 65MnN4OH zig zag 70CoN4 zig zag 70CoN4OH zig zag 75Fe2N5 bulk 60Fe2N5OH bulk 60MnCoN5 bulk 60MnCoN5OH bulk 60Graphene 110Arm chair edge 90Zig zag edge 85

* some but not all bonds broken

FeN4OH arm chair

FeN4OH zig zag

FeN4OH bulk

Highlight: Successful completion of initial set of library calculations for bulk-C structures


Accomplishment: High-throughput Synthesis and CharacterizationPurpose: Utilize Argonne’s robotic system, simultaneous pyrolysis, high-throughput structural characterization using XRD and XAFS, and multi-channel flow double electrode cell for ORR activity characterization to explore catalyst composition and heat treatment effects.Catalyst system: LANL’s (AD)Fe-N-C selected due to high RDE ORR activity

Parameters varied to obtain 40 unique samples: Fe-to-Zn ratio: 0, 1, 2.5, 5, and 7.5 at% Fe in precursors Fe salts: sulfate, nitrate, acetate Heat-treatment temperatures: 900, 1000, 1100°C

Precursor synthesis: CM Protégé Robot

0.0 0.2 0.4 0.6 0.8 1.0

-0.00018-0.00016-0.00014-0.00012-0.00010-0.00008-0.00006-0.00004-0.000020.000000.00002

Curre

nt (A

)

Potential (V vs. RHE)

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10 20 30 40 50 60 70

Inte

nsity

2 Theta

FeC 1100C #2

FeN 1100C #2

FeS 1100C #2

Heat Treatment

Characterization


Progress: High-throughput Characterization of (AD)Fe-N-C

• High-throughput synthesized (AD)Fe-N-C has same Fe XAFS as LANL’s (AD)Fe-N-C

• Fe acetate- and Fe sulfate-derived (AD)Fe-N-C have similar atomic structure; Fe nitrate results in Fe species with lower oxidation state

• Pyrolysis temperature and Fe content have a large effect on Fe atomic structure and oxidation state

• Crystalline Fe species formed is Fe carbide; carbide content increases with Fe content and pyrolysis temperature

• Ongoing steps: High-throughput hydrodynamic ORR activity measurements; electrode fabrication and testing

Fe Nitrate

Fe Acetate

Fe Sulfate

LANL Fe Sulfate0 at% Fe1 at% Fe

2.5 at% Fe

5 at% Fe

10 at% Fe

Fe Salt Effect: 1 at% Fe 1000°C Fe Content Effect: FeSO4 1100°C


Purpose: Elucidate the nature of ORR active sites and discover materials with enhanced ORR activity using PGM-free thin films with well-controlled composition and structure

Capability Development: Model System Synthesis & Characterization

PVD SynthesisCapability: Combinatorial Synthesis and Spatially-Resolved Characterization• Multi-element thin films of nanoparticles (metals, oxides, nitrides, sulfides)• Gradients (composition, temperature, film thickness, nanoparticle size, etc.)• Physical vapor deposition techniques (sputtering, pulsed laser deposition) • Supports (highly oriented pyrolytic graphite, metals, glass, etc.)• Characterization by XRF, XPS, XRD, etc.• Electrochemical characterization being developed

RBS

Thick film to determine deposition conditions

FeN/C interface by thin film deposition

Summary:Demonstrated first Fe-C-N model systems with composition similar to active catalysts

Next step: Perform RDE testing of ORR activity to asses catalytic performance of the model systems

XRD

Fe-N composition controlled by Fe, N, T Tetrahedral FeN formed

• Fe-N bonds present in FeN thin films

• C-N bonds formed at FeN/C interface

• Formation of FeN4 moiety in carbon matrix likely

XPS


Purpose: Accelerate the optimization of the electrode composition and structure for PGM-freecatalysts by developing methods for the high-throughput synthesis and deposition of catalyst-ionomer-solvent inks, and measuring ORR activity and fuel cell performance, using:

• Combinatorial 25-electrode segmented electrode hardware from NuVant (ANL)

• Segmented fuel cell hardware (NREL)

Capability Development: Combinatorial Fuel Cell Performance Testing

Demonstrated for measuring ORR activities

Identical iR-corrected H2-air polarization curves for different channels

Resistance uniformity in need of improvement

Cross-talk between segments of cell hardware with common GDL quantified

Several approaches investigated to mitigate cross-talk and enhance ability to test combinatorial samples: (i) parallel flow field design; (ii) segmented GDLs; (iii) segmented electrodes

0.4

0.6

0.8

1

0 0.1 0.2 0.3 0.4

iR-F

ree

Volta

ge (V

iR-fr

ee)

Current Density (A/cm2)

Ch7

Ch8

Ch9


Collaborations• ElectroCat members: Four National Laboratories with highly complementary skills and

capabilities in catalyst development and advanced characterization, electrode structure design and modeling, MEA fabrication, and electrochemical and fuel cell testing:

Los Alamos National Laboratory – ElectroCat Co-lead Argonne National Laboratory – ElectroCat Co-lead National Renewable Energy Laboratory Oak Ridge National Laboratory

• No-cost collaborators not directly participating in ElectroCat:

University at Buffalo (SUNY), Buffalo, New York – novel PGM-free catalysts

Technical University Darmstadt, Germany – catalyst characterization by Mössbauer spectroscopy and synchrotron X-ray techniques

CEA – LITEN/DEHT/SCGE, Grenoble, France – MEA optimization and characterization Fraunhofer ICT, Pfinztal, Germany – PGM-free catalyst corrosion (DEMS studies) Colorado School of Mines, Golden, Colorado – XPS characterization University of Warsaw, Poland – PGM-free catalyst corrosion studies (DEMS studies) Pajarito Powder, LLC, Albuquerque, New Mexico – catalyst scale-up and

commercialization (license of a LANL PGM-free catalyst in 2016) Chevron Energy Technology Company, Richmond, California – CRADA on non-

electrochemical applications of PGM-free carbon-based materials


Summary• ElectroCat launched in February 2016: effort initially focused on consortium development,

followed by PGM-free catalyst and electrode R&D and capability demonstration and development for last nine months

• Consortium Development National laboratories with capabilities relevant to PGM-free catalyst development and

implementation were selected and Steering Committee established A public ElectroCat website was inaugurated in February 2016 and the national laboratory

capabilities posted (www.ElectroCat.org) A data management hub was established based on Globus and leveraging the Materials

Data Facility data publication capabilities A streamlined CRADA template and NDA completed, approved, and is available for use

• Performance Improvement Demonstrated hydrogen-air performance of 120 mA/cm2 at 0.8 ViR-free with (CM+PANI)-

Fe-C(Zn) cathode catalyst, a 25% improvement over the 2016 status Achieved half-wave potential (E½) of 0.83 V with (AD)Fe-N-C in RDE testing, an increase

of 0.02 V over the 2016 status PGM-free catalyst activity in an MEA: 16 mA/cm2 at 0.90 ViR-free and 0.044 A/cm2 at 0.87 V

• Characterization and Capability Development Determined >10× lower Fe dissolution rate with (AD)Fe-N-C than (CM+PANI)-Fe-C(Zn) Obtained direct evidence of a majority of Fe sites being atomically-dispersed and on the

(AD)Fe-N-C catalyst surface using TEM, a molecular probe and X-ray spectroscopies


Summary (Continued)

Using TEM and nano-CT, elucidated the source of performance limitations and identified pathways to improving (AD)Fe-N-C fuel cell performance

Synthesized 40 variations of (AD)Fe-N-C catalyst and characterized atomic structure using high-throughput X-ray diffraction and spectroscopy

• Characterization and Capability Development Synthesized and characterized the composition of model thin-film FeN/C catalyst Obtained 9 mV ORR half-wave potential agreement for Pt/C and < 30 mV agreement for

PGM-free catalyst between RDE and multi-channel flow double electrode measurements Developed and utilized the capability to characterize by XAFS the atomic structure of

catalysts during heat treatment Developed a PGM-free cathode performance model considering the effects of flooding,

mass, and charge transfer and applied it to the (CM+PANI)-Fe-C cathode

• ORR active-side activity and durability modeling Developed durability descriptor calculation automation (DDCA) approach to determine

the values of knock-on displacement threshold energy (KODTE), a durability descriptor Completed the initial set of 25 KODTE values for various metal-N4 sites in the bulk and

on arm-chair and zig-zag edges of graphene sheets in PGM-free catalysts

• Project performance measures ElectroCat milestones and quarterly progress measures (QPMs) for all four labs either

completed or on track


Remaining Challenges and Barriers

• Oxygen reduction reaction activity of PGM-free ORR catalysts in continued need of further improvement to reduce cathode thickness and lower cost of other stack components

• Insufficient long-term stability and performance durability under steady-state and load-cycling conditions

• Limited understanding of the ORR mechanism, nature of the ORR active site and mechanism of catalyst degradation preventing rational design of next-generation PGM-free catalysts

• Low volumetric density of active sites

• Electrode design and component integration to provide adequate ionic, electronic, and mass transport to and from active sites

• Replacement of Fe in catalyst with another PGM-free transition metal not catalyzing hydroperoxy radical formation and ionomer degradation

• Integration with existing automotive fuel cell stack and system technology


Future Work

• Consortium Development Incorporate collaborators from DE-FOA-0001647 into ElectroCat and coordinate activities

of all ElectroCat partners; Update ElectroCat website with information from FOA projects, status of capabilities,

publications; Implement capabilities to mint DOIs and other identifiers with persistent landing pages for

datasets and to support automated data capture and publication; Document ElectroCat Data Sources: (i) formats, (ii) associated metadata, (iii) sharing

needs, and (iv) dataset comparison or integration needs; Execute intellectual property management plan and material transfer agreements.

• Performance and Durability Improvement Advance activity of atomically dispersed catalysts by maximizing concentration and

accessibility of active centers through (i) the development of novel synthesis approaches, (ii) optimization of hierarchical pore-size and ionomer distribution, and (iii) decreasing electrode tortuosity

Explore (AD)Fe-N-C parameter space for improved performance and durability using high-throughput activity, durability, and performance testing of 40 materials synthesized to date

Determine primary factors governing the durability of PGM-free catalysts, concentrating predominantly on homogenous and thus easier to study materials

Further develop surface-specific methods for the ORR active-site determination

Any proposed future work is subject to change based on funding levels


Future Work (Continued)

• Characterization and Capability Development Active site identification, influence of Fe-N-C ratio on ORR activity, and influence of

synthesis parameters on active site formation: (i) thin-film model systems; (ii) ex situ, in situ, and operando X-ray spectroscopies and electron microscopy; (iii) high-throughput catalyst synthesis, characterization, and activity testing.

ORR kinetics and mechanisms: (i) in-cell kinetic measurements as a function of oxygen partial pressure, temperature, cell voltage, etc., (ii) electrochemical techniques in aqueous electrolytes.

Degradation mechanisms/durability: (i) on-line ICP-MS-RDE to correlate active with catalyst component loss; (ii) ex situ and in situ tomography, spectroscopy, and microscopy; voltage-loss analysis using polarization curves and impedance spectroscopy.

Electrode optimization: (i) segmented cell combinatorial studies of electrode performance coupled with high-throughput catalyst-ink synthesis and deposition; (ii) tomography and electron microscopy/EDX visualization of solid, pore, and ionomer distribution coupled with electrode transport modeling

• ORR active-side activity and durability modeling, including high-throughput Improved, automated analysis scripts Application to variety of structures Analysis of “poisoning” effects of different moieties by comparison to *OH binding energy

Any proposed future work is subject to change based on funding levels


Co-AuthorsPGM-free catalyst development, electrochemical and fuel cell testing, atomic-scale modelingPiotr Zelenay (PI), Laura Barber. Hoon Chung, Edward Holby, Siddharth Komini Babu, Ling Lin, Ulises Martinez, Geraldine Purdy, Xi Yin

High-throughput techniques, mesoscale models, X-ray studies, aqueous stability studiesDebbie Myers (PI), Nancy Kariuki, Magali Ferrandon, Ted Krause,Jaehyung Park, Dali Yang, A. Jeremy Kropf, Rajesh Ahluwalia, C. Firat Cetinbas, Voja Stamenkovic, Eric Coleman, Haifeng Lv,Pietro Papa Lopes, Ian Foster, Ben Blaiszik, Liz Jordan

Catalyst modification, model catalyst development, advanced fuel cell characterizationHuyen Dinh (PI), Yun Xu, Andriy Zakutayev, Thomas Gennett, K.C. Neyerlin, Guido Bender, Michael Ulsh, Kristin Munch, Robert White, Eric Payne

Advanced electron microscopy, atomic-level characterization, XPS studiesKarren More (PI), David Cullen, Harry Meyer III, Brian T. Sneed


Technical Back-Up Slides


Progress: Effect of EW and Ionomer Content on Catalyst Performance

460

460

420

420

440

420

720 830 110025

35

45

55

Current density at 0.65 V (mA/cm2)

Iono

mer

Wei

ght (

%)

EW (g/mol SO3H)

300320340360380400420440460480

Anode: 0.3 mgPt cm-2 Pt/C H2, 200 sccm, 1.0 bar H2 partial pressure; Cathode: (CM+PANI)-Fe-C(Zn) ca. 4.8 mg cm-2 (no hot-pressed), air, 200 sccm, 1.0 bar air partial pressure; Ionomers: Nafion D521 (EW 1100), Aquivion D83 (EW 830), Aquivion D72 (EW 720); Membrane: Nafion,211; Cell: 5 cm2, 80 °C

• Current density at 0.65 V used as a descriptor of fuel cell performance of (CM+PANI)-Fe-C(Zn) catalyst• Based on the voltammetric response, higher catalyst utilization achieved with higher ionomer content• Performance at 0.65 V correlating well with catalyst utilization (electrochemical surface area)


j (m

A/c

m2 )

-20

-10

0

10

20

3025 wt%35 wt%45 wt%55 wt%

Nafion EW = 1000Nafion EW1100


Accomplishment: In Situ RDE-ICP/MS of PGM-Free CatalystsQuadrupole mass filter

Horizontal torch

• Stability of PGM-free catalyst is significantly affected by high potential excursions (start-stop conditions)

• Dissolution of Zn occurs at potentials greater than 1.4 V

• Small but measurable Fe dissolution occurs at high potentials together with Zn dissolution

• Substantial increase in iron dissolution in Fe3+/Fe2+ redox region - more than observed before scan to 1.7 V

Loading: 0.3 mg/cm2

Potential limit: 0.08 to 1.7 V vs. RHE

Fe2+ region and entire Zn region are more unstable after 1.7 V

LANL (AD)Fe-N-C: 2.5 at% Fe, 1100°C, H2SO4-treated


Progress: Combinatorial Hydrodynamic Screening of Catalyst Activity

0.0 0.2 0.4 0.6 0.8 1.0

-0.00018-0.00016-0.00014-0.00012-0.00010-0.00008-0.00006-0.00004-0.000020.000000.00002

Curre

nt (A

)


0.0 0.2 0.4 0.6 0.8 1.0-0.00003

-0.00002

-0.00001

0.00000

0.00001

0.00002

Curre

nt (A

)


-0.0008

-0.0006

-0.0004

-0.0002

0.0000

0.0002

0.0004

0.0006

0.0008

Cur

rent

(A)


RDE Background M-CFDE Background

0.0 0.2 0.4 0.6 0.8 1.0

-0.0020

-0.0015

-0.0010

-0.0005

0.0000

Curre

nt (A

)


M-CFDE ORRRDE ORR

Multi-channel double electrode cell (m-CFDE) E½ agrees with RDE to 30 mV for PGM-free catalyst and within 9 mV for PGM catalyst. Automated deposition will improve agreement.

ORR, 18 µgPt/cm² TKK 46 wt% Pt/C catalyst, 0.1 M HClO4

0.6 mg/cm2 of LANL’s (CM+PANI)-Fe-C(Zn) catalyst; 0.5 M H2SO4


Accomplishment: Magnetic Purification of PGM-free Catalyst

SEM

XRD of the magnetic purification process: removal of spectator crystalline Fe species

Magnetic purification procedure SEM and EDS mapping Fe of the magnetic purification process

2θ (degree)

20 40 60 80

Inte

nsity

(a.u

.)

1st heat treatmentAcid leachingMagnetic separation2nd heat treatment

Iron sulfideIronIron carbide

Before magnetic purification

After magnetic purification

SEM Fee

• Large spectator magnetic Fe species effectively removed bymagnetic purification

• Well-dispersed Fe in catalyst achieved after magnetic purification

Fee


Progress: Activity Descriptor Calculation Automation Developed

Successful automation of efficient structure relaxation via MAST toolkit • Future version to script adsorbate placement,

pull calculated energies from output files, andprint UL and potential determining step to file

• Application to bulk-hosted structures MN4 (M = Mn, Fe, Co) MN4(*OH) (M = Mn, Fe, Co) M2N5 (M = Fe2, MnCo) M2N5(*OH) (M = Fe2, MnCo)

• Application to AC-edge-hosted structures MN4 (M = Mn, Fe, Co) MN4(*OH) (M = Mn, Fe, Co)

• Application to ZZ-edge-hosted structures MN4 (M = Mn, Fe, Co) MN4(*OH) (M = Mn, Fe, Co)

• Next Steps: Improved, automated analysis scripts Application to variety of structures Analysis of “poisoning” effects of different

moieties by comparison to *OH binding energy


Progress: Catalysts based on Di-iron Complexes

Anode: 0.3 mgPt cm-2 Pt/C H2, 200 sccm, 30 psig back pressure; Cathode: ca. 4.8 mg cm-2 air, 500 sccm, 30 psig

pressure; Membrane: Nafion,211; Cell: 5 cm2, 80 °C

• Several Di-iron complexes synthesized and tested as adsorbates on a carbon support• Further development stopped after poor performance measured in a fuel cell (LANL

QPM FY17 Q2)

Current density (A/cm2)

0.00 0.02 0.04 0.06 0.08 0.10V

olta

ge (V

)

0.0

0.2

0.4

0.6 Fe-DPDA Complex

Fe-NDPFA Complex Fe-DPA Complex

Evaluated Di-iron Complexes

Fe-DPDA Fe-DPA

Fe-NDPFA


Progress: (CM+PANI)-Fe-C Catalyst Performance in O2 and Air

MEAs with (CM+PANI)-Fe-C cathode catalyst, SGL 24BC diffusion media• Anode: 0.2 mgPt/cm2 Pt/C, Cathode: ~4 mg cat/cm-2, Membrane: Nafion 211,

Cell active area: 5 cm2

• Cathode electrode thickness: 85 ± 5 µm; Ionomer: 35 wt.%, 17.3 vol.%; Catalyst (Fe+C): 65 wt%, 35.7 vol%; Porosity (XCT) 47%; I/C: 0.54

• 0.044 A/cm2 at 0.87 V (iR-free) in H2-O2 at 1 bar P(O2); 69-88 mV/dec apparent TSDistributed ORR Kinetics Model

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0.9

0.0 0.5 1.0 1.5 2.0 2.5 3.0

E +

IR (V

) / H

FR (Ω

.cm

2 )

Current Density, A/cm2

80oC100% RH

HFR

H2/O2P(O2)=2 bar

H2/O2P(O2)=1 bar

H2/O2P(O2)=0.3 barH2/Air

P(Air)=1 bar

200

300

400

500

600

0.01 0.10 1.00 10.00

Cat

hode

Ove

rpot

entia

l (η c

c ), m

V


Air(1 bar)

O2(0.3 bar)

O2(1 bar)

O2(2 bar)

Catalyst Catalyst Loading Mass Activity Catalyst Activity

Pt/C 0.1 mg-Pt/cm2 443 A/g-Pt 44.3 mA/cm2

a-Pt/C 0.1 mg-Pt/cm2 316 A/g-Pt 31.6 mA/cm2

d-PtNi/C 0.1 mg-Pt/cm2 665 A/g-Pt 66.5 mA/cm2

(CM-PANI)-Fe-C 4 mg-cat/cm2 1.8 A/g-cat 7.2 mA/cm2

η𝑐𝑐𝑐𝑐 = 𝜂𝜂𝑐𝑐 + 𝑖𝑖𝑅𝑅Ω𝑐𝑐 (𝑖𝑖𝛿𝛿𝑐𝑐𝑏𝑏𝜎𝜎𝑖𝑖

)

𝑖𝑖 = 𝑖𝑖0𝑃𝑃𝑂𝑂2γ 𝑒𝑒

α𝑛𝑛𝑛𝑛𝑅𝑅𝑅𝑅 η𝑐𝑐

*Pt/C, a-Pt/C, and d-PtNi from Johnson Matthey. See FC106 AMR presentations for pol curves and catalyst details.


Breakdown of Voltage Losses (80 °C, 100% RH)

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500

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Kin

etic

Los

s (η

c), m

V


Air(1 bar) O2(0.3 bar) O2(1 bar)

O2(2 bar)

0

50

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150

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300

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Mem

bran

e O

hmic

Los

s, m

V


Air(1 bar)

O2(0.3 bar)

O2(1 bar)

O2(2 bar)

0

100

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ansf

er O

verp

oten

tial,

mV


Air(1 bar)

O2(0.3 bar)O2(1 bar)

O2(2 bar)

0

40

80

120

0.0 1.0 2.0 3.0 4.0

Cat

hode

Ohm

ic L

oss

(iRΩ

c ), m

V


•55 mV/dec Tafel slope•Doubling catalyst activity or loading leads to 16 mV gain in cell voltage

•Non-uniform ORR in thick CL•ORR shifts toward membrane interface at high current densities

•Dominant loss mechanism in H2-air at high current density•Need new catalyst support and electrode structure

LANL (CM+PANI)-Fe-C Catalyst


Capability Development: Fluorine Doping of (AD)Fe-N-C Catalyst

C O N Fe F Zn Al

Before doping 89.0 6.1 3.7 0.9 0.0 0.2 0.0

After doping 78.7 9.2 2.8 0.3 5.8 0.2 3.0

XPSBefore doping After doping

Fe 1s

Purpose: Prevent flooding of thick PGM-free electrodes by imparting hydrophobicity to catalyst with fluorine doping


0.2 0.4 0.6 0.8 1.0

Cur

rent

den

sity

(mA

cm-2

)

-3

-2

-1

0Before F dopingAfter F doping

• No morphological change after fluorine doping• F successfully doped (5.8 at.%), either within C network or bridge-bonded with two carbons;

however, Fe content decreased from 0.9 to 0.3 at.% causing decrease in ORR activity

ElectroCat (Electrocatalysis Consortium)Overview Timeline • Start date (launch): Feb 1, 2016 ......

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Transcript of ElectroCat (Electrocatalysis Consortium)Overview Timeline • Start date (launch): Feb 1, 2016 ......